Radio Frequency Qualification Facilities David Florida Laboratory , Canadian Space Agency/Government of Canada , Ottawa , Ontario K2H 8S2 , Canada.
E2IP , 750 Boulevard Marcel-Laurin , Saint-Laurent , Quebec H4M 2M4 , Canada.
ACS Appl Mater Interfaces. 2019 Oct 23;11(42):38880-38894. doi: 10.1021/acsami.9b08854. Epub 2019 Oct 9.
Screen printing is the most common method used for the production of printed electronics. Formulating copper (Cu) inks that yield conductive fine features with oxidation and mechanical robustness on low-temperature substrates will open up opportunities to fabricate cost-effective devices. We have formulated a screen-printable Cu metal-organic decomposition (MOD) ink comprising Cu formate coordinated to 3-(diethylamino)-1,2-propanediol, a fractional amount of Cu nanoparticles (CuNPs), and a binder. This simple formulation enables ∼70-550 μm trace widths with excellent electrical [∼8-15 mΩ/□/mil or 20-38 μΩ·cm] and mechanical properties with submicron-thick traces obtained by intense pulse light (IPL) sintering on Kapton and poly(ethylene terephthalate) (PET) substrates. These traces are mechanically robust to flexing and creasing where less than 10% change in resistance is observed on Kapton and ∼20% change is observed on PET. Solderable Cu traces were obtained only with the combination of the Cu MOD precursor, CuNP, and polymer binder. Both thermally and IPL sintered traces showed shelf stability (<10% change in resistance) of over a month in ambient conditions and 10-70% relative humidity, suitable for day-to-day fabrication. To demonstrate utility, light-emitting diodes (LEDs) were directly soldered to IPL sintered Cu traces in a reflow oven without the need for a precious metal interlayer. The LEDs were functional not only during bending and creasing of the Cu traces but even after 180 min at 140 °C in ambient air without losing illumination intensity. High definition television antennas printed on Kapton and PET were found to perform well in the ultrahigh frequency region. Lastly, single-walled carbon nanotube-based thin-film transistors on a silicon wafer were fabricated with a screen-printed Cu source and drain electrodes, which performed comparably to silver electrodes with mobility values of 12-15 cm V s and current on/off ratios of ∼10 and as effective ammonia sensors providing parts per billion-level detection.
丝网印刷是生产印刷电子产品最常用的方法。在低温基底上形成具有氧化和机械强度的导电精细特征的铜（Cu）油墨，将为制造具有成本效益的器件开辟机会。我们已经配制了一种可丝网印刷的 Cu 金属有机分解（MOD）油墨，该油墨由与 3-（二乙基氨基）-1,2-丙二醇配位的 Cu 甲酸盐、少量的 Cu 纳米颗粒（CuNPs）和粘结剂组成。这种简单的配方可以在 Kapton 和聚对苯二甲酸乙二醇酯（PET）基底上通过强脉冲光（IPL）烧结获得约 70-550μm 的细线宽度，具有出色的电学性能[约 8-15mΩ/□/mil 或 20-38μΩ·cm]和机械性能，得到的细线厚度小于亚微米。这些痕迹在 Kapton 上弯曲和起皱时具有机械强度，电阻变化小于 10%，在 PET 上电阻变化约为 20%。仅使用 Cu MOD 前体、CuNP 和聚合物粘结剂的组合才能获得可焊接的 Cu 痕迹。无论是热烧结还是 IPL 烧结的痕迹，在环境条件和 10-70%相对湿度下，其电阻的稳定性超过一个月（<10%的电阻变化），适合日常制造。为了证明其用途，直接将发光二极管（LED）在回流炉中焊接到 IPL 烧结的 Cu 迹线上，而无需使用贵金属中间层。这些 LED 在 Cu 迹线弯曲和起皱时不仅可以正常工作，甚至在环境空气中 140°C 下放置 180 分钟后，也不会失去照明强度。在 Kapton 和 PET 上打印的高清晰度电视天线在超高频区域表现良好。最后，在硅晶片上制造了基于单壁碳纳米管的薄膜晶体管，其具有丝网印刷的 Cu 源极和漏极，其性能与银电极相当，迁移率值为 12-15cm V s，电流导通/关断比约为 10，并且可以作为有效的氨传感器，提供十亿分之一级别的检测。
